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dealt with in the chapter on mineral oils (see p. 368), have a basis of sulphori-
cinate or sulpholeate.

Analysis of Turkey-red oil comprises the following determinations and
tests, the second and fifth being of special importance for the evaluation
of the product.

1.  Solubility  and   Emulsivity.—2  or   3   c.c.   of   the,  oil   and  as
much water should give complete solution and addition of about 10 vols.
of water should then yield a persistent homogeneous emulsion of a faintly
acid reaction.

Dilute ammonia should also dissolve the oil completely and the solution
should remain clear on dilution with a. large quantity of water.

2.  Total Fat.—10 grams of the oil are heated somewhat in a conical
flask with 50 c.c. of water, 25 c.c. of dilute hydrochloric acid (i : 5) being
added and the liquid boiled for 3-5 minutes (until the fused fat becomes
clear), allowed to cool, transferred to a separating funnel, into which the
flask is washed with a little water and with 200 c.c. of ether.    The whole
is vigorously shaken and allowed to stand, the acid aqueous liquid being
removed and the ethereal solution washed with three successive quantities
of 15 c.c. of water, these wash waters being added to the aqueous acid liquor
and this kept for the determination of the sulphuric acid (sea 3, below).
The bulk of the ether is distilled from the ethereal solution in a conical
flask and the residue transferred to a tared beaker;   when the remainder
of the ether has evaporated, the residual mass is dried for 1-2 minutes over
a naked flame (a medium flame being passed under the beaker until the
fat ceases to froth) and then for half an hour in an oven at 105° and weighed.
The weight of fat thus found, multiplied by 10, gives the percentage of
total fat in the oil.

The fat may then be used for investigating the nature of the oil as in 5

3.  Determination   of  the   Sulphuric   Acid.—The   aqueous   liquid
obtained as above is precipitated with barium chloride, the weight of barium
sulphate thus precipitated corresponding with the total sulphuric acid (S03)
in the oil.

On the other hand the sulphuric acid as ammonium or sodium sulphate
is determined by treating 10 grams of the oil with saturated sodium chloride
solution (quite free from sulphate), filtering through a moist filter, washing
well with the saturated sodium chloride solution, diluting the filtrate and
precipitating the sulphate in it with barium chloride.

Subtraction of the percentage of S0;i as ammonium or sodium sulphate
from the total percentage gives the sulphuric acid (as S03) as sulphoricinate
and this, multiplied by 4725, gives the percentage of sulphoricinoleic acid
in the oil.

4.  Neutral Fat.—30 grams of the oil are dissolved (in a separating
funnel) in 50 c.c. of water, 20 c.c. of ammonia solution and 30 c.c. of glycerine.
The whole is shaken with two successive quantities of 100 c.c. of ether and
the united ethereal solutions washed several times with water and then
distilled, the residue being dried at 100° and weighed.    This weight, multi-
plied by 3$$-, gives the percentage of neutral fat in the oil.  i             '      (0*070)                            1